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From:   Miklos Szeredi <miklos@szeredi.hu>
Date:   Fri, 5 Feb 2021 16:28:26 +0100
Message-ID: <CAJfpegvxb9bfbBpoa6R8UENwL9m6BSU84kr50PBSssUJYc8wFQ@mail.gmail.com>
Subject: Re: [PATCH 03/18] ovl: stack miscattr
To:     Vivek Goyal <vgoyal@redhat.com>
Cc:     Miklos Szeredi <mszeredi@redhat.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
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On Fri, Feb 5, 2021 at 4:25 PM Miklos Szeredi <miklos@szeredi.hu> wrote:
>
> On Fri, Feb 5, 2021 at 12:49 AM Vivek Goyal <vgoyal@redhat.com> wrote:
>
> > > +int ovl_miscattr_set(struct dentry *dentry, struct miscattr *ma)
> > > +{
> > > +     struct inode *inode = d_inode(dentry);
> > > +     struct dentry *upperdentry;
> > > +     const struct cred *old_cred;
> > > +     int err;
> > > +
> > > +     err = ovl_want_write(dentry);
> > > +     if (err)
> > > +             goto out;
> > > +
> > > +     err = ovl_copy_up(dentry);
> > > +     if (!err) {
> > > +             upperdentry = ovl_dentry_upper(dentry);
> > > +
> > > +             old_cred = ovl_override_creds(inode->i_sb);
> > > +             /* err = security_file_ioctl(real.file, cmd, arg); */
> >
> > Is this an comment intended?
>
> I don't remember, but I guess not.  Will fix and test.

Sorry, yes, problem is that there's no file pointer available at this point.

Fix is probably to introduce security_inode_miscattr_perm() hook.

Thanks,
Miklos